Sequential circuits samplers

I picked up a Prophet 2000 the other day and it needs some love to get back up and running.  

What behavior will a disk drive than needs to be replaced display?  Mine powers up and the motor turns, but I can not get a sample disk to load.  I get an iF (incorrect format) message.  I am not sure if all the sample disks that came with it are corrupt.  I doubt they all would be, though I haven't tried them all.  I also was unable to format a disk MF2DD type, which I think are the same as DSDD.  

Does anyone have the schematic?

The main issue has to do with the output.  When I plug in headphones I get clean sound out the right channel only.  When I plug into an amp, I get somewhat clear sound for 1 voice and crackley noisy sound when more than 1 voice is used.  Still nothing much out the left channel, every once in a while it will sound when both mono jacks are used.

For the 1st 7 presets when I press the same key repaetedly it will sound 4 times then silent 4 times then sound 4 times, ect.  Presets 8-12 will sound for all key strikes.

Thanks for any help,
Bob